Miniaturization of Microstrip λ/4 Stepped-Impedance-Resonator Filters Using Low Impedance Microstrip with Inserted Ground Strips

• Main Authors: Cheng-Hsien Liang, 梁正憲
• Other Authors: Chi-Yang Chang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/t5war5

碩士 === 國立交通大學 === 電信工程系所 === 95 === A new method to miniaturize microstrip step impedance resonator structure is proposed in this theses. Inserting ground strips in the low impedance microstrip segment results in a high effective capacitance that makes the characteristic impedance lower. Therefore, the characteristic impedance of the microstrip line is mainly controlled by the signal strips and the inserted ground strips in coplanar manner. The concepts and characteristics of this modified resonator structure are described in detail. Practical applications for planar bandpass filters employing the features of this resonator structure are discussed and fabricated. Besides, additional cross coupling structure which produces a pair of transmission zeros near the passband is also introduced to improve the skirt characteristics. Both simulated and measured results are presented.